Abstract
Atomic layer deposition (ALD) was used to prepare a thin alumina layer on Fischer–Tropsch catalysts. Co-Pt-Si/γ-Al2O3 catalyst was overcoated with 15–40 cycles of Al2O3 deposited from trimethylaluminum (TMA) and water vapor, followed by thermal annealing. The resulting tailored Fischer–Tropsch catalyst with 35 cycle ALD overcoating had increased activity compared to unmodified catalyst. The increase in activity was achieved without significant loss of selectivity towards heavier hydrocarbons. Altered catalyst properties were assumed to result from cobalt particle stabilization by ALD alumina overcoating and nanoscale porosity of the overcoating. In addition to optimal thickness of the overcoat, thermal annealing was an essential part of preparing ALD overcoated catalyst.
Highlights
Fischer–Tropsch (FT) is a flexible synthesis route that converts synthesis gas into liquid fuels and chemicals [1,2,3]
We present the effect of varying Atomic layer deposition (ALD) layer thickness and the temperature annealing method on catalyst activity and selectivity
Hydrocarbon analyses for C6 -C20 and C1 -C9 n-alcohols were performed with a Shimadzu GC-2014 (Rxi-5HT, i.d. 0.32 mm × 30 m × 0.10 μm df) and heavy hydrocarbons ranging from C10 to C80+ were analyzed with a high-temperature HP5890 gas chromatograph with an on-column injection port and a CP-SimDist UltiMetal separation column (i.d. 0.53 mm × 10 m × 0.17 μm df, 1 m retention gap)
Summary
Fischer–Tropsch (FT) is a flexible synthesis route that converts synthesis gas into liquid fuels and chemicals [1,2,3]. ALD overcoatings are considered as conformal films on planar substrates, uneven island growth might occur with catalyst samples [19]. This overcoating island growth results from varying growth regimes depending on the number of deposited cycles, favoring specific surface locations especially at initial ALD cycles (
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
